The Great Slaughter: Losing Whales led to the near loss of the Marine Holobiont:

 

A recent article on "The Atlantic" shows that we are starting to understand how the ecosystem has been enormously changed by human activity. Destroying the whales, during the 19th and 20th century, has completely changed the marine ecosystem. Basically, whales feed (ingest) at all depths, but poop (egest) near the surface, recycling nutrients for the plankton to use, then for the krill to eat plankton-- and then be eaten by whales. So, whales fertilize the ocean. Without whales, it becomes a desert. It may well be that the evolution of whales were one of the factors that started the ice age that has been lasting for the past 30 million years or so.

https://www.theatlantic.com/science/archive/2021/11/whaling-whales-food-krill-iron/620604/

https://www.nature.com/articles/s41586-021-03991-5

So, whales are part of the marine holobiont system: species that interact while acting for their self-interest but, in doing so, benefit the whole system. As usual, onward, fellow holobionts!!